Policy —

Stealth turns 40: Looking back at the first flight of Have Blue

The forerunner of the F-117 Stealth Fighter flew for the first time 40 years ago this month.

Enlarge/ One of the two Have Blue prototypes sits in a hangar at Lockheed's Skunk Works in Burbank, California in this 1978 photo. The aircraft was the first real "stealth" aircraft, designed to have a radar cross section the size of "an eagle's eyeball".

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On December 1, 1977, a truly strange bird took flight for the first time in the skies over a desolate corner of Nevada. Looking more like a giant faceted gemstone than something designed to lift-off, the aircraft (nicknamed the "Hopeless Diamond") had been flown out to Groom Lake in parts aboard a Lockheed C-5 Galaxy cargo plane.

While much of the Hopeless Diamond was a conglomeration of spare parts from other existing aircraft, it was the first of a new breed—the progenitor of Stealth. Hopeless Diamond was the first of two technology demonstrators built for a program called "Have Blue," an initiative program spawned from a Defense Advanced Research Projects Agency effort to create an aircraft that could evade the Soviet Union's increasingly sophisticated integrated air defense systems.

Forty years have passed since the Have Blue project's two demonstrator aircraft—built on a relative shoestring budget by Lockheed's Skunk Works—flew over the Nevada desert and ushered in a new era. Over time, the engineering, physics, and mathematics that created the Have Blue prototypes would be refined to create the F-117 Nighthawk stealth fighter and serve as the basis for the designs of the F-22 Raptor and F-35 Lightning II.

This miltech evolution began because Lockheed was willing to internally fund an effort to win a program from which it had been essentially excluded by DARPA. Using its engineering talent, some sophisticated mathematics, and the best computing technology of the day, Lockheed's Skunk Works rapidly created a prototype on the cheap. That prototype demonstrated what Lockheed Martin Skunk Works Senior Fellow Edward Burnett described to Ars as "our one miracle"—an aircraft shape that had a radar cross section smaller than a bird's.

The invisible rabbit

A poster for the movie Harvey, which inspired the name of the DARPA stealth research program.

The story of Have Blue begins with a DARPA effort called Project Harvey—named for the invisible six-foot-three-and-a-half-inch rabbit from the play and film of the same name. The future of integrated air defense systems had already proved effective in the last years of the Vietnam War. It combined long-range radar that could detect high-flying attack aircraft from hundreds of miles away, electronic warfare sensors that could detect the ground-following radar of low-flying aircraft passively, and radar-guided surface-to-air missiles and anti-aircraft guns. And a Defense Science Board study in 1974 concluded through war-gaming out an air war with the Soviet Union in a conventional invasion scenario—specifically, the Fulda Gap scenario at the center of most Cold War military strategy at the time—that the US had to develop some technology to counter those defenses.

So in 1975, DARPA kicked off Project Harvey. The challenge would have seemed like an ideal fit for Lockheed's Skunk Works, given that the organization had been producing "low observable" aircraft for the CIA and Air Force for years. The previous U-2 surveillance plane wasn't technically a "stealth" aircraft, but it was coated in radar absorbent material. The same was true of the A-12 "Oxcart"/SR-71 "Blackbird" and the D-21 supersonic reconnaissance drone, which were intentionally designed to have a reduced radar cross section and painted with radar absorbing "iron ball" paint. Despite its size, the design of the SR-71 reduced its radar cross section to that of a Piper Cub, making it difficult for long-range radars to detect (at least until it was too late for someone to shoot at it).

The Lockheed U-2 spy plane was not specifically designed for stealth—it was supposed to fly high above the altitude at which air defenses could take it down. But it was painted with an early version of the radar-absorbent material that gave early stealth aircraft that menacing black color.

US Air Force

The SR-71, Lockheed's supersonic spy plane (here shown in its training variant, the SR-71B), had a radar cross section similar to a Piper Cub, thanks to its profile and radar-absorbing coating.

USAF / Judson Brohmer

The D-21 drone, designed by the Lockheed Skunk Works, had an even smaller radar cross section, and was used in an attempt to watch Chinese nuclear test sites. But its radar return was still larger than that of the "Hopeless Diamond"

Lockheed Martin

But this was a stealth fighter project, and Lockheed had not built a fighter jet for over a decade. While Lockheed had experience with low radar cross-section aircraft, its work was so classified that the DARPA project team didn't know about it. As such, DARPA didn’t initially invite Lockheed to the dance. General Dynamics, Fairchild, Grumman, McDonnell Douglas and Northrop were instead asked—but only McDonnell Douglas and Northrop RSVP'd for $100,000 each to craft initial entries.

Ironically, at about the same time, Denys Overholser—a Skunk Works mathematician and radar expert—discovered equations in a nine-year old research paper from Russian scientist Pyotr Ufimtsev. Recently translated by the Air Force's Foreign Technology Division, the paper reworked some of Maxwell's Equations to predict the radar reflectivity of a geometric shape. In his memoir, then-Skunk Works chief Ben Rich called the equations the "Rosetta Stone breakthrough for stealth technology."

The equations were eventually used as the basis for a computer program called Echo 1, which would allow engineers to break down the design of an aircraft into a series of triangles to calculate their radar cross section for any particular angle of attack. From there, this allowed engineers to optimize the shape of an aircraft for the smallest possible radar return.

Rich, who was fighting to keep the Skunk Works afloat during a turbulent period in Lockheed's business history, was already trying to convince DARPA to let his team join the competition. "Ben went around and made sure that the people who were in control of Project Harvey were actually briefed in on some of the things that had been done before," Burnett said. "That really helped to get DARPA to say, 'We'll let you compete on your own dime.'"

That decision ended up being in Lockheed's favor. According to Rich, DARPA actually offered to let the Skunk Works work on Harvey for a symbolic one dollar payment. Lockheed refused it—and as a result, all the work Lockheed did would remain proprietary to the company. (Accordingly, in 1993, Lockheed was ultimately granted a patent for the Have Blue concept.)

Overholser had already suggested a "faceted" design to reduce radar signature for the initial design submission for the Harvey project, but Echo 1 showed that there were issues with the first attempt because of diffraction. Using the software, the design team was able to sort through the 20 design candidates quickly to find the one with the most optimized radar cross section.

The diamond-like look of the design was largely dictated by the limits of the computing hardware of the day. "Some of the mathematics were being done on slide rules still, and a PDP-8 and other like computers, so yeah, computer limitations really kept the shaping down," Burnett told Ars. "We were just really beginning to understand the mathematics of the physics that govern this technology."

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Sean Gallagher
Sean is Ars Technica's IT and National Security Editor. A former Navy officer, systems administrator, and network systems integrator with 20 years of IT journalism experience, he lives and works in Baltimore, Maryland. Emailsean.gallagher@arstechnica.com//Twitter@thepacketrat

Love the article. I worked with the F117 program in the 90's. There are a few interesting tidbits I could add if I felt inclined to violate the 75 year NDA they made me sign when I left the program in 1998. The thing is, they really wouldn't add much to the story. I love how much is available these days from completely unclassified sources. Well done!

Edit: One I can think of that is unclassifed: We were told the Radar Absorbent Material (RAM) was akin to a third weapons bay. The F117 has 2 weapons bays and a typical weapons load was a 2000 lb laser guided bomb in each bay. The RAM coating weighed about 2000 lbs itself, so the reduced Radar Cross Section was like carrying a third weapon.

Edit: A second anecdotal (I can't confirm aspects of it) story. The F117 should properly be called an A117. It has no internal gun and the only time it ever fired an air to air weapon was in testing. They supposedly locked one of the launch racks in the down position to fire the missile. Once it had successfully launched an air to air missile, the "F" designation could be applied. The reason they wanted the "F" instead of the "A"? While many fighters (F16s and F117s for example) were capable of dropping nuclear bombs, "A" designated aircraft counted as launch platforms in the nuclear arms treaties and "F" designated did not.

If any one is curious, many of the prototype aircraft used to develop these (and other) technologies are on display now (and have been for some years) at the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Dayton, Ohio.

Tacit Blue, the YF-16, and many more are on display. If you are ever in the area, I highly recommend that you take a day (or more) to stop and walk through the museum. It will blow your mind...

If any one is curious, many of the prototype aircraft used to develop these (and other) technologies are on display now (and have been for some years) at the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Dayton, Ohio.

Tacit Blue, the YF-16, and many more are on display. If you are ever in the area, I highly recommend that you take a day (or more) to stop and walk through the museum. It will blow your mind...

Love the article. I worked with the F117 program in the 90's. There are a few interesting tidbits I could add if I felt inclined to violate the 75 year NDA they made me sign when I left the program in 1998. The thing is, they really wouldn't add much to the story. I love how much is available these days from completely unclassified sources. Well done!

Edit: One I can think of that is unclassifed: We were told the Radar Absorbent Material (RAM) was akin to a third weapons bay. The F117 has 2 weapons bays and a typical weapons load was a 2000 lb laser guided bomb in each bay. The RAM coating weighed about 2000 lbs itself, so the reduced Radar Cross Section was like carrying a third weapon.

Edit: A second anecdotal (I can't confirm aspects of it) story. The F117 should properly be called an A117. It has no internal gun and the only time it ever fired an air to air weapon was in testing. They supposedly locked one of the launch racks in the down position to fire the missile. Once it had successfully launched an air to air missile, the "F" designation could be applied. The reason they wanted the "F" instead of the "A"? While many fighters (F16s and F117s for example) were capable of dropping nuclear bombs, "A" designated aircraft counted as launch platforms in the nuclear arms treaties and "F" designated did not.

A designation or B?. I know that the B52, B1 and B2 are nuclear capable, would have never thought that the A10 could be counted as a nuclear platform.

Love the article. I worked with the F117 program in the 90's. There are a few interesting tidbits I could add if I felt inclined to violate the 75 year NDA they made me sign when I left the program in 1998. The thing is, they really wouldn't add much to the story. I love how much is available these days from completely unclassified sources. Well done!

Edit: One I can think of that is unclassifed: We were told the Radar Absorbent Material (RAM) was akin to a third weapons bay. The F117 has 2 weapons bays and a typical weapons load was a 2000 lb laser guided bomb in each bay. The RAM coating weighed about 2000 lbs itself, so the reduced Radar Cross Section was like carrying a third weapon.

Edit: A second anecdotal (I can't confirm aspects of it) story. The F117 should properly be called an A117. It has no internal gun and the only time it ever fired an air to air weapon was in testing. They supposedly locked one of the launch racks in the down position to fire the missile. Once it had successfully launched an air to air missile, the "F" designation could be applied. The reason they wanted the "F" instead of the "A"? While many fighters (F16s and F117s for example) were capable of dropping nuclear bombs, "A" designated aircraft counted as launch platforms in the nuclear arms treaties and "F" designated did not.

A designation or B?. I know that the B52, B1 and B2 are nuclear capable, would have never thought that the A10 could be counted as a nuclear platform.

Yeah, the SALT and START treaties only covered strategic bombers. I think that the "F" versus "A" designator has to do with the weapons load that could be carried, vs. nuclear capability. The F-117A only had two weapons bays, and could carry a maximum of 4,000 lbs of bombs. "A" attack planes are specifically intended for heavy ground attacks. The A-10 can carry up to 16,000 lbs of "mixed ordnance", and the A-6 could carry 18,000 lbs.

"That tech led into the YF-16 and the development of the F-16." The YF-16 was the first aircraft designed from scratch with a fly-by-wire system, and its first (unintentional) flight was in January of 1974.

At this risk of sounding pretentious, I would suggest that this paragraph be corrected.

The first production aircraft to be designed from scratch with a fly-by-wire system was the Avro Canada CF-105, which first flew in 1958. The CF-105's flight computer was the origin of what we now consider the defining characteristics of fly-by-wire:- All flight surfaces actuated by electrical or electric-over-hydraulic actuators under computer control- Flight envelope and stability characteristics defined and enforced by the computer- Artificial feel (force feedback) on the control stick- Flight computer integrated with radar and electronic navigation systems

The plane was designed so that it could even be flown on autopilot from ground control if necessary, although the program was cancelled before this capability was fully validated. It was also intended to be supercruise-capable; the first one to have the Orenda PS.13 Iroquois engines with this capability was just a few days away from demonstrating it when the program was cancelled.

The CF-105 was scrapped for political reasons in 1959, and Avro Canada effectively died with it. Most of the engineers were snapped up by aerospace firms contracted to NASA and the US DoD, and they took the expertise and technology with them.

The F-16's analog computer was a direct descendent of the one designed for the CF-105, drawing heavily on the experience of the engineers that General Dynamics got out of the Avro Canada collapse.

(Source: The CF-105 project was remarkably public and well-documented for a military program. Also, my grandfather was among the Avro staff who actually wired up the thing's flight controls.)

Having been born in Burbank (as were my parents Glendale/Burbank) and raised in a house just across from the airport/Skunk Works, I have always been interested in the history of what was going on just across Vanowen Street.

Ben Rich's Book "Skunk Works: A Personal Memoir of My Years at Lockheed" is a great read and filled in a lot of gaps.

My parents had several friends that worked for Lockheed/Skunk Works and one of them was a guy named Dick Madison.

We were in a camping club with several families, including the Madisons.

I distinctly remember hearing news of a top secret plane going down in Nevada and that the military had cordoned off a HUGE area to keep everyone away from the crash site.

Friday (May 5th, 1978) we arrived at Puddingstone Lake (San Dimas, CA) for our monthly club camp-out. Dick Madison was already there and setup. Shortly after we arrived, a helicopter circled overhead and then landed nearby. Dick got on the helicopter and we didn't see him again until the next club camp-out.

I remember my dad asking him "How was Nevada?" and he just looked back and winked.

Ben Rich's book filled in the missing pieces.

When Have Blue 1001 was being built, the machinist union at Lockheed went on strike - so the people that would have normally completed the assembly of the aircraft were not available. Wanting to meet the deadline, they had shop-supervisors (management who were not under the union) complete the work. Dick Madison, as it turns out, was the supervisor responsible for the landing gear.

On May 4th, 1978, HB1001 was lost in the crash mentioned in this article and Ben Rich's book. On that day's test flight, the landing gear had been damaged when the pilot was attempting to land. Not sure if the gear would hold on another landing attempt, and not wanting to risk the pilot's life, they had him take it back up and circle around while they exhausted other options. Eventually, it ran out of fuel and the pilot ejected.

Because Dick Madison was the expert on the landing gear, they interrupted his planned weekend camping trip to have him come help with the investigation.

Love the article. I worked with the F117 program in the 90's. There are a few interesting tidbits I could add if I felt inclined to violate the 75 year NDA they made me sign when I left the program in 1998. The thing is, they really wouldn't add much to the story. I love how much is available these days from completely unclassified sources. Well done!

Edit: One I can think of that is unclassifed: We were told the Radar Absorbent Material (RAM) was akin to a third weapons bay. The F117 has 2 weapons bays and a typical weapons load was a 2000 lb laser guided bomb in each bay. The RAM coating weighed about 2000 lbs itself, so the reduced Radar Cross Section was like carrying a third weapon.

Edit: A second anecdotal (I can't confirm aspects of it) story. The F117 should properly be called an A117. It has no internal gun and the only time it ever fired an air to air weapon was in testing. They supposedly locked one of the launch racks in the down position to fire the missile. Once it had successfully launched an air to air missile, the "F" designation could be applied. The reason they wanted the "F" instead of the "A"? While many fighters (F16s and F117s for example) were capable of dropping nuclear bombs, "A" designated aircraft counted as launch platforms in the nuclear arms treaties and "F" designated did not.

A designation or B?. I know that the B52, B1 and B2 are nuclear capable, would have never thought that the A10 could be counted as a nuclear platform.

I don't believe the A or B designation makes it automatically count as a nuclear platform. I think if the aircraft is nuclear capable and it carries one of those designations, then it counts.

Lockheed developed have blue on their dime. No government funding or contract. No bought and paid for demo model to show design.

No cost plus contract that automatically goes 500% over budget.

The first stealth aircraft, and it was an r&d project paid for by a company. Not a government buy.

That there is why the F-35 is billions over projected budget, why for the $500 billion we have spent so far the baby could build and man an entire carrier battle group. (A carrier is $12 billion or like 20 f-35's)

Love the article. I worked with the F117 program in the 90's. There are a few interesting tidbits I could add if I felt inclined to violate the 75 year NDA they made me sign when I left the program in 1998. The thing is, they really wouldn't add much to the story. I love how much is available these days from completely unclassified sources. Well done!

Edit: One I can think of that is unclassifed: We were told the Radar Absorbent Material (RAM) was akin to a third weapons bay. The F117 has 2 weapons bays and a typical weapons load was a 2000 lb laser guided bomb in each bay. The RAM coating weighed about 2000 lbs itself, so the reduced Radar Cross Section was like carrying a third weapon.

Edit: A second anecdotal (I can't confirm aspects of it) story. The F117 should properly be called an A117. It has no internal gun and the only time it ever fired an air to air weapon was in testing. They supposedly locked one of the launch racks in the down position to fire the missile. Once it had successfully launched an air to air missile, the "F" designation could be applied. The reason they wanted the "F" instead of the "A"? While many fighters (F16s and F117s for example) were capable of dropping nuclear bombs, "A" designated aircraft counted as launch platforms in the nuclear arms treaties and "F" designated did not.

I thought the F-117A designation came from the USAF “hiding” the Nighthawk within the numbering system of the MiGs being flown by the Red Eagle squadron that also operated out of Tonopah.

For example, their MiG-17F was called a YF-114C in the flight logs. By using YF-117A for the Nighthawk, anyone without clearance who might have gotten hold of the logbooks would just think it was another MiG that had been appropriated by the Red Eagles through various means (like buying them from a county like India that was a MiG customer but not completely in the Soviet sphere of influence).

One top-Secret program concealed the other in this way, which was really clever.

OK. It appears the Syrians tagged an F 35 not long ago. They tagged it with a SA5/S200 from the late 60s of last century. Now they have recently gained the advantage of integration with the Russian anti air network of radars. The ones that guide the S400.

What appears to have happened is that the F 35, although stealthy from the front, are not very stealthy at all from behind. Some examination, rather supports this theory.

No, Russian propaganda claims they did.

Meanwhile Israel sustains they've never used the F-35 in combat, but that one was damaged in a bird strike two weeks before the supposed incident. Seeing how they don't even have a full strength squadron I don't see why they'd risk it.

OK. It appears the Syrians tagged an F 35 not long ago. They tagged it with a SA5/S200 from the late 60s of last century. Now they have recently gained the advantage of integration with the Russian anti air network of radars. The ones that guide the S400.

What appears to have happened is that the F 35, although stealthy from the front, are not very stealthy at all from behind. Some examination, rather supports this theory.

No, Russian propaganda claims they did.

Meanwhile Israel sustains they've never used the F-35 in combat, but that one was damaged in a bird strike two weeks before the supposed incident. Seeing how they don't even have a full strength squadron I don't see why they'd risk it.

It was actually Syrian propaganda, but I take your point. However the Israeli announced the bird strike that day,, no matter when they claimed it occurred.

OK. It appears the Syrians tagged an F 35 not long ago. They tagged it with a SA5/S200 from the late 60s of last century. Now they have recently gained the advantage of integration with the Russian anti air network of radars. The ones that guide the S400.

What appears to have happened is that the F 35, although stealthy from the front, are not very stealthy at all from behind. Some examination, rather supports this theory.

No, Russian propaganda claims they did.

Meanwhile Israel sustains they've never used the F-35 in combat, but that one was damaged in a bird strike two weeks before the supposed incident. Seeing how they don't even have a full strength squadron I don't see why they'd risk it.

The idea behind 'stealth' is to enable the Shoot First capability doctrine. That is, kill him before he sees you. It doesn't make the plane invisible and an adversary will always find ways to counter your capability. Blind luck comes into play at times.

Will never forget as a young boy my dad showing me a (London) Times newspaper article about the Skunk Works and the development of stealth fighters - these phrases, 'Have Blue' and 'Tacit Blue' seemed like exotic code words that brought a whole new level of mystery and intrigue to a military tech-minded kid. Researching the projects, eagerly awaiting further leaks and (gasp! photos and artist impressions) was so exciting.

Anyone who is interested in the history of the U-2, the Blackbirds, and by extension some of the work done on stealth in the early days should read the mass of documents on the programs that the CIA have declassified.

The main problem they faced was that Soviet radars improved far faster than expected so they were detecting U-2s almost as soon as they took off and could track them throughout their flights. This was despite the service ceiling of the aircraft being well above the supposed maximum detection altitude of the radar, which had been based on Western hardware donated during WW2.

Project Rainbow sought to the radar cross section of the U-2 but the realised improvements weren’t great and came at the cost of significantly reduced performance. The follow-on Archangel concepts were an attempt to address the U-2s limitations with a clean sheet design that could deliver much higher speeds, higher cruising altitudes, and much smaller RCS. Archangel design 12 became the A-12 OXCART which was further evolved into the larger, but somewhat slower and lower-flying SR-71. The Blackbirds were stealthy to an extent but they stuck out like a sore thumb on longer wavelength radars such as those used for air traffic control. They also took much longer to come into service than had originally been hoped, and by the time they did, the threat environment had become far more serious with the introduction of the S-200. In the event of a failure of their sophisticated ECM packages, they were at serious risk of being shot down. In the end it didn’t matter because overflights of Soviet territory had been banned in 1960 and the advent of satellite imaging with its lack of political or military risk consigned the Blackbirds to flying over relatively much less dangerous targets.